In the micro, you're right that financial performance is not going to be impacted by one waterfall or one broken animatronic. However, these issues will build up and create the impression of decay if they become a pattern.
An example of a theme park that went through this process is Disneyland Paris. Disneyland Paris, following the devastation that was the opening of Walt Disney Studios Paris, went into deep cost-saving mode. That meant the amount of repainting was slashed, ride maintenance was curtailed, effects were turned off, and landscaping and other small features decayed.
A well built theme park can take a lot of abuse and still end up being presentable. The experience is worse, but it's still pretty good. But inevitably, the abuse takes its toll and the entire place becomes increasingly run down and broken. By the early 2010s, Disneyland Paris was an in atrocious shape. And Attendance was stagnate and Euro Disney SCA continued to lose money. Cue "Project Sparkle." Today, Disneyland Paris is making money consistently again. Why? Because the necessary investments needed to make Disneyland Paris "show ready" have been made. People don't want to visit a dystopian amusement park when they pay $150 to enter. They want to see some actual effort.
The same was true of Disneyland's early 2000s malaise. The mid 2000s focus on quality brought Disneyland into a resurgent period, setting the stage for the transformation of Disney California Adventure.
Theme parks are a really good business. Iger somehow failed to realize this, until his "deathbed conversion" in 2023. But people have been making these points on these boards for decades that consistent investment, adequate capacity, and good value will lead to Disney Park's lasting for decades.